The invention relates to an inflatable object, in particular an air mattress.
An air mattress of this type is known from U.S. Pat. No. 3,155,991. This air mattress has within the inflatable section an independent pump section which is opened by a spring. This pump section terminates at one end in a diaphragm valve, and a small opening in the wall surrounding the diaphragm valve facilitates equalization of pressure. A one-way inlet valve is provided for the entry of air into the pump section. This embodiment does not require inflation of the pump section by mouth or by an external bellows. However, this embodiment is structurally rather elaborate.
An air mattress of similar arrangement is known from U.S. Pat. No. 3,042,941. In this known air mattress, the head section serves as the pump section and comprises a self-spreading formed body which ensures that after compression during the pumping action, the pump section is again pushed open and air can again enter via a one-way inlet valve. In the wall, which is arranged between the pump section and the section to be inflated, is placed a diaphragm valve without flowback facility. In another form of the embodiment, this diaphragm valve is replaced by a permanently open flow-through channel of considerably smaller diameter relative to the one-way inlet valve. This is to ensure that the pressure between the section to be inflated and the pump section is equalized.
In both cases, the element which affects the spreading of the walls of the pump section has to be entered prior to sealing of the pump section, which is cumbersome from a manufacturing point of view. Furthermore, the user of these known air mattresses can feel the element which spreads the wall in the form of a noticeable resistance, which is possibly also optically visible, and is also undesirable. Furthermore, rolling the air mattress is impeded by the shaped spreading bodies.
An air mattress with an integrated pump is known from EP 0 078 763. The head section of this mattress forms a sealed pump container, the dimensions of which are defined by inflatable chambers. The pump container is connected to the lying section of the mattress via a non-return valve. By pressing the head section together, which can be done by the foot of the user, air is conveyed into the lying section. However, the head section cannot be subjected to internal pressure, its hardness is instead determined by the inflatable chambers. In addition thereto, it is necessary to initially inflate the chambers by mouth or by means of a bellows. A desirable even pressure in the head section and in the lying section is usually not achievable.